Apparatus for surfacing sheets or plates



Sept. 7 1926.

H. HITCHCZOCK APPARATUS FOR SURFACING SHEETS OR PLATES l, 1922 12 sheets-sheeb 1 Filed June H MZk [N van/rm? Sepia 3' g M269.

' H. K. HRTCHCOCK APPARATUS FOR sunmcws smms OR PLATES Filed June 1,1922 12 Sheets- -Sheet 1N vew 70R Sept. 7,19%. mama H. K. HITCHCOCKAPPARATUS FOR SURFAGING SHEETS 0n PLATES Filed June 1, 1922 12 snezwneet5 m VENTOK Sept. 7 1926. 1,598,724

H. K. Hn'cHcocK APPARATUS FOR SURFACING SHEETS OR PLATES Filed June 1.1922 j 12 sheets snet 1 m3 cs Se t; 7, 192 1,598,720

H. K. HITCHCOCK v APPARATUS FOR SURFAGING SHEETS OR PLATES Filed June 1,1922 l2 Sheets-Sheet 5 I 8 I m INVEN 7 0R H. K. HITCHCOQK APPARATUS FORSURFACING SHEETS OR .LATES Filed Jun 6 1. 1.922 12 Sheets-Sheeo 6m/vexvroe Sept. 7, 1926. 1,598,720

H. K. HITCHCOCK' APPARATUS FOR SURFAGING SHEETS O R PLATES Filed Jun 1,1922 12 Sheets-Sheet '7 gym WM/Q Sept. 7 '1926.

H. K. HITCHCQCZK APPARATUS FOR SURFAGING SHEETS OR PLATES Filed June 11922 12 Sheets-Sheec 8 m y I a Nu; m "1 w LL Q W Y m i H. H WCZ H mm; H.

APPARATUS FOR SUREAGING SHEETS OR PLATES Filed June 1, 1922 1.2 sheets-Sheec 9 H. K. HITCHCOCK APPARATUS vFOR SURFACING SHEETS OR PLATES Sept.Y}. 19%, 1,598,720

Filed June 1, ,1922 12 Sheets-Sheet l0 FIEZD.

HJK W.

Sept. 7 1926. mwm

H. K. HITCHCOCK APPARATU S FOR SURITACING SHEETS OR PLATES Filed June 1,1922 12 Sheets-Sheec l 3 i if 5.5

1H 1&5 F33 /NVW70R Patented Sept 7, i926.

UNIT-ED STATES HALIBEBT K. HITCHCOCK, OF PITTSBURGH, PENNSYLVANIA,ASSIG-NDR TO IPITTS- I BURGH PLATE GLASS COMPANY, A CORPQBATION 6FPENNSYIW'ANIA.

APPARATUS FOR SURFACING SHEETS OR PLATES.

Application filed June 1,

The invention relates to apparatus for surfacing glass sheets or platesof glass or other material, i. e. grindino or polishing the surface ofthe sheets or both, and, as applied to glass sheets, is designedparticularly for work upon. the smaller sizes. The apparatus isillustrated as applied to the surfacing of square sheets, but it Will beunderstood that it is designed for use upon, and may be used to the sameadvantage with, sheets of a'vvide variety of shapes andproportions.

One object of the invention is the provision of an apparatus whichrequires no setting of the sheets upon supporting tables by- "the use ofplaster or other means as is now commonly done. A- further object is theprovision of an apparatus in which the work of grinding and polishingmay be carried out in a continuous operation. A still further object isthe provision of an apparatus of the character stated. which is in ,alarge degree. automatic, requiring only a minimum amount of handlahoriand attention. The foregoing and other objects aresecured by theapparatus as hereinafter described and illustrated in the accompanyingdrawings wherein:

Figure l is a plan view of the apparatus; Fig. 2 is a partial sectionand partial side elevation Figs. 2, 2" nd 2 are detail views showing themeans for adjusting the drive shafts of the tables: Fig. 3 is an endelevation of the apparatus at the left-hand end of Fig. 1; Fig. 4 is anend elevation at the right-hand end of Fig. i; Fig. 5 is a diagrammat cplan view of one oit'the tables illustrating the sand distrilnitionllfig. (i is a section through the construction of Fig. 5; Fig. 7 is a\wrtieal section on the line vll- VII of Fig. 8: Fig. Sis a'partial sideelevation and partial section on the line VIII Vlll o't Fig. 7; Fig. 8is a section on the line Vl.ll--Vl.ll of Fig. 7; Fig. 9 is a par tialtop \i-cW and partial bottom vie \\j ,ot the suction dev ce employed torsupporting the sheets to llt. surtaced. the upper lett hund quarter ofthe view showing the bottom of one ot the sucker devices; Fig. 10 is apartial side elevation and partial vertical scd ion of the suct ondevice oi Fig. 5); Figs. 11.. 12 and 13 are detail views showing themethod of incoming the suction devices. Fig. 11 being an end elevation,Fig. 19. a side elevation and F g. 13 a bottom plan View; Fig. 14; is asectional view showing a modification of the 1922. Serial No. 565,053.

method of supporting the suction devices which method is preferred; Fig.15 is a partial plan view of one form of table with all but a smallsection of one otthe runner bars removed; Fig. 16 is an enlarged sectionon the line XVIXVI of Fig. 15; Fig. 17 is a plan view of one of therunner bars; Fig. 18 is a side elevation, partially in section, of therunner bar of Fig. 17; Fig. 19 is a plan view of a modified tableconstruction; Fig. 20 is a transverse section through. the constructionof Fig. 19; Fig. 21 is a plan view oilf one of the polishing tables;Fig. 22 is a transverse section through the construction of Fig. 21;Fig. 23 is an enlarged detail section through a small section oi thepolishing table; Fig. 24 is a partial plan view of another term ofgrinding table construction;

Fig. 25 is a partial side elevation of and partial section through theconstruction ot Fig. 2 1-; and l igs. 2t} and 2? are plan and sideelevation views. respectively of one of the runner bars of the Fig. 2tconstruction. Briefly stated the apparatus, in the preterrcd l'orm, comn'ises a series of rubbing beds in the term of relatively large rotatingtables whose upper faces are provided with suitable grinding and polishileans, in combination with. an endless ca er provided with a largenumber of plate or sheet support ng elements to which the sheets arercleasably secured and which carries the sheets over the series ofrubbing beds in paths such that-a uniform wear. (as nearly as ispossible) is secured upon the surfaces at the tables or beds. Duringthis period of movement. the plates are (l) rough around, a grouml moreand more finely by tne'use of liner and liner abrasive. and finallypolished. after which the plates are turned upside down with respect tothe supporting elements, and the surfacing operation repeated upontheother sides thus presented to the rubbing beds. The number of tables orbeds required will vary, depending upon the size of the tables and uponthe flatness of the glass plates to be surtaced and the character of thesurfaces thereof. might be possible in some cases to complete the grinding operation on asingle large table. The abrasive which is preterahi;ed is sand, which is applied in a plural of grades upon a single tableor bed. no grade first used being the coarsest, Wit grades progressivelytollo 1 liner and liner lltl is gradually ground and its surface becomessmoother.

The devices for supporting the plates are preferably vacuum memberswhich are automatically engaged with the plates at the beginning of thecycle and automatically released at the end. These devices may beactuated (pressed down on the glass plates) several times during thecycle to insure their continued holding action upon the plates, and areguided by an overhead track so as to secure a spiral path of movement ofthe plates as they move circumferentially around the tables, whicharrangement serves to distribute the work of grinding over the entiresurface of the tables.

Referring first to the general arrangement as shown in Figs. 1 to 4, theprincipal parts of the apparatus may be enumerated as follows:

A, B, C, and D are annular driven grind ing tables or rubbing bedshaving their upper surl'aces provided with grinding or surfacing means;E, F G and H are polishing tables similar to the grinding tables, buthaving their upper faces provided with a polishing niediuim such as feltor pitch; I 1, etc. are a series of plates to be surfaced,

such plates being in the present instance.

sheets ol plate glass supported by suitable carrying devices whichrelcasably grip the upper surfaces of the plates; J is an overheadcarrying tracl; upon which thb carrying devices are mounted, suchtrack'extending, as indicated in Fig. 1 circumlerentially around each ofthe tables and from one table to the next, so that the plates may becarried smrcessively over all eight ol the tables; l\' is a conveyor atthe lel'l-haud end of th apparatus l'or carryingthe plates beneath thebelt devi e l, which scrvcs automatically to secure the plate supportingdevices to the plates preliminary to their passage over the'tirstgrinding table M is a receiving conveyor also located at the leit'-hamlcnd of the apparatus for l'ccc-iving the Iinished plates alter they havebeen released l'rom the carrying devi es by means of the beltreleasir'ig device N; t), IQQ .and it are a eries of sprockets overwhich the endless carrying belts tor the sheet carrying devices pass inthe movement from one end of the. c lc starting with the con\'c \'or Kand liuishing with the conveyor M; S isthe motor lrv means of which theendless carrier device is driven; 'l (Fig. :3) is one ol the. motors fordriving the grinding and polishing tables, each table being drivenindependently by its own motor; ll is the sand grader whi h is employedl'or grading the sand whi h is applied to the lirsl three tables A. itand and V is a platl'orm, shown in Fig. l a partially broken away.

whi h is lo at d between the grinders and' polishcrs below the drivingmechanism for the endless carrier and serving to give convenient amessto such mechanism.

The method of supporting and driving the grinding and polishing tablesis shown in Fig. 2. As here shown the table is driven from beneath, thedriving mechanism being located in the chamber 1 which is preferablylined with concrete. The weight of the table is supported upon a head 1carried by the spindle 2 arranged so that when the spindle is-loweredthe weight of the table is transferred to the track 1, and the head thendisconnected from the table. The spindle 2 is supported in the cylindrical base member 3 at its lower end and adso justable vertically by meansof the wedge 4 interposed between the top of the member 3 and flan e ofthe plunger 5. The thrust of the spindle 2 is taken by the bearingplates l (Fig. 2). The wedge 4 is tapered as inas dieated in Fig. 2 andheld in adjusted position by the screw 1, and the plunger 5 is raisedand lowered by the application of hydraulic pressure in the cylinder 3.This adjustment of the table is desirable in order 9 to maintain thegrinding surface of the table at the same level as such surface isworntdown in service. The shaft of the motor drives the bevel gear 6 inthe manner indicated and such gear (5 is mounted (:5 upon a shortvertical shaft which has at its upper end a pinion (not shown), meshingwith the spur gear 7, which is keyed to the spindle 2. The usual trough8 (Fig. 2) is provided beneath the. edge of each table to m receive themixture of "'ater and abrasive which runs from the. table, and in theEase ol the three grinders A, B and C, this mixture is conducted back toa sump or pit lying beneath the grader U (Fig. l) aml from which thegrader is supplied by means of a suitable pump.

The. grader itself is preferably of the type shown in the llechtelPatent No. 1,089,894, issued March ltlth ltlll, such tank being nomodilied, however, to supply abrasive simultaneously to the three tablesA, ll and (l instead of to two; as shown'in the. patent, and beingarrang d to supply several grades of abrasive to each ta le at the sametime. H5 'lhis modili aliozrmeans only th addition of more outlet pipesthan illustrated in the Bechtel patent, the method of operation beingprecisely the same. the abrasive and water running l'rom tlmtablcs beingcolleclled and returned to the sump beneath the' grader, after which itis rc; radcd and cir v culatcd in a routinuous cycle. 'lhepipes. forconducting the abrasive to the table are shown'in Fig. 5, there beingfour of Q the r pipes fl. 1!). ll and 12 in this particular instance,although the number maybe increased or de reased to suit requirements.The vertical portions ol' the pipes (Fig. ii) are secured to asupporting mast l3 5115- pended from above with the lower ends extendeddiagonally, and braced by means of .the spider ll carried upon the lowerend of the must. The pipe 9 supplies the coarsestabrasive, the abrasivesupplied through the pipes 10. 11 and 12 being of increasing fineness.The table A has its central portioncut out, as indicated at 15, so as toprovide the annular grinding bed, and in order to assist in get-tingthe'coarse abrasive from the first pipe 9 between the plates to beground and the surface of the-bed, the lower end of: the pipe 9 isrecurved, as indicated at 16 in Fig.6 and suppliesthe Water and abrasiveupwardly across the bevel 17 at the inner edge '5 the table. The otherpi es lOpll and 12 a iie extended over the ta lo and supply the abrasivedownwardly as indicated at 18 in Fig. 6, the discharge in each caseoccurring closely adjacent the plates on the table.

The p lates of glass 1 to be ground in their passage to the table, overit, and away from it, 'l'ollow the path of the track J heretoiorerehirrrd to in the general description. The plates are lowered so thattheir faces engage the surface of the table when they reach the point a,at which point the coarse sand is applied. This sand is utilized indoing the roughest grii'iding until the plate arrives at the point I),at which point the iext 'finer. grade of abrasive is applied. The thirdgrade of abrasive is applied at the point 0 and the last It will beobserved that the grinding. starts when the plates are at the station anext to the inner periphery of the annular table and that, as thegrinding progresses, the plates are carried gradually-outward until theyreach the periphery of the table at re, where the plate is lifted out ofcontact with the table. The vath pursued substantially spiral carryingthe plates over the entire grinding"s11rfaco of the table, whicharrangeinent accomplishes the function of equalizing "the wear over thegrinding area of the table, sothst its surface is reduced.lllllfolllll), and thus kept flat. The rotation of the table causes theabrasive to work outward th the outer edge, so that very lit! lo of thecoarse sand supplied at one station is carried around to the point itapplica tion of the next finer grade at the next station. in ordcr toprevent. the coarser sand, from the station 0 from reaching the station(Z. the scraping: device or liatile 520 is preferably employed betweenthe two stations. such ballle having its lower edge provided with asheet of rubber or other flexible material in contact with the surfaceof the subbing bed. Another similar scraper Ql is. provided intermediatethe station it ah'd the inner perpihery of the table in order to, direct'the line sand outwardly and prevent such sand from renrziiningupon the of any undue strain to the 21 2 having their faces grade at thepoint (1.

table until station a is reached, as such fine sand tends to interferewith the action ojE- the coarser abrasive supplied at the station a.

Although the system herein illustrated and described discloses threegrinding ta bles A. 13 and (l for use in connection with the grindingwith sand, it may be possible to entirely smooth the surface of theglass upon a single table by making such table of sullicient size andp'rovi iling a sutlicient numb-er of ditl'erent grades of' sand. 'In,their niovon'ient around the table, the plates of glass are free androtate about their vertical axes, by reason. of the constructionhereinafter more fully set forth, and the mounting is also madeflexible, so that the glass can adjust itself to thesurfacelof thetable. These features facilitate the grinding' of the plates and avoidthe application plates tending to break them, such as would be-the caseit they were rigidly mounted andnot tree to rotate.

The grinding surfaces of the tables may be variously constructed ashereinafter set forth, the'iorin illustrated in Fig. ins volving the useof cast iron runner blocks 'ooved in the. curved fornrindicatcd at 22 inthis ligureand also in Fig. 19. The runner bars are bold to a suitablesupporting framework 22 (Fig. 6). the sand circuinl'erentially andprevent it from being; fed too rapidly across and oil of the table, itbeing desirable that the sand supplied at each. station should becarried around and utilized until the plates reach the next station.

The overhead track J and the devices for supporting the plates I andcarrying them along the track are shown in detail in Fig. 9 to 13. Thetrack J is made up of the twosets o1 angle irons 2323 and 2+l--24 shownin Figs. 11 and 12 and between these angles are *1 c series of spindles25 mounted for vertical rnoven'ient and each provided its lower endwith, a vacuum frame 26,

shown in detail in Figs. 5) and 1t). l lach spindle 25 is mounted forrotation in :1 casing 27 and such casing is provided with short lateralbearing; shafts 28 upon which are mounted the wheel 29 arranged as indicated in Fig. 11. The spindle casings 2'? ::.so carry the lateralbrackets :30. shown in l?ig. 12 upon which are mounted the veriical pins31 carrying the rollers 32 which engage the inner vertical flanges otthe trr :l; angles 23 and 24. I

The spindle ilmibly secured at its lower end to the vacuum frame '30,asindicated in Figs. 9 and 10a The lower end of the spindle is taperedand his into a block 33, in which it is secured by means of the pin 37.This block is provided with three till The grooves employed tend todirect arms 34 secured to the flexible coupling plate 35 by means of thebolts 38. This plate is preferably of spring steel or woven fabricimpregnated with rubber and is secured at its outer edge to the vacuumframe form-illustrated, with a collar 39 at the juncture of the radialarms 4-0. Each sucker device is made up. of the two plates of rubber 41and 42, the plate l2 being the glass ongaging member and the plate itthe member for producing the suction client. The plate ll has embeddedin it: the metal plate 43 carrying), theheaded pin 44 normally held inupper position by means of the spring,"

41'). The lower end 0t this pin is provided with a rubber tip 46, whichserves to engage the glass and disengage it from the sucker, ashereinafter set forth, when the pin it is pressed downwardly to asullieient extent. The lower plate -12 has a skeleton l ranieworlt ll ofmetal, around which the l'lllllnl' s molded. and this skel ton iu niherZltll the edge of the plate ll. are secured to the va uum frame 2 bymeans of the series of bolts to. The lower tare ol' the plate 42 ispreferably provided with grooves it), as shown in Fig. .l. The spacebetween the plates -t-l and i2 constitutes the vacuum chamber which isredu ed in volume when the plate 4; is pressed down.

means of the s rew .35.

'lhe spindle cat-in; 2T. :-l\o\\'|\ in Figs. ll nu l 11-. is providedwith a yoke :ll into which the upper end (it the spin-lie projerts. suchupper end being" provided with a thrust hearing 5:! in two parts withinterposed balls. as shown. lressnre is applied to hold the spindle downby means ol' the coil spring 52) which bears at its upper end aga nst aplate 54.. which is in turn adjusted in position by Means are providedt'or raising the spindle so as to litft the glass carried thereby abovethe surface of? the tables in the form of the lever 56 ivote'd to thevole 51 at T and provided wit 1 the arm 5H having at its ends suitableanti-friction rollers engaging the lower side of the thrust bearinp 52.The lower plate of the thrust hearing is secured to the spindle againstlongitudinal movement thereon by any suitable means. so that the upwardmovement of the lever 28 lifts the spindle and the vacuum devil-escarried at the lower end thereof.

The extreme upper end of the lever at; carries a roller 5!), andlitting'eams (30 are. provided along the path of travel of the spindleswhere necessary in order to secure the lifting 6, of such spindles.There is one of these lifts ing cams in position to enga e the rollers59 and lift the spindles just be ore the table A is reached so that thesheets carried by the spindles are above the surface of the table asthey pass onto such table. This cam terminates at the station marked ain Fl. 5, permitting the s indles to lower at this point so that the seets engage the surface of the table. The next lifting cam is locatedwith its forward end at the station a of Fig. 5, at which point; thespindles and the sheets carried thereby are lifted from the table andmaintained in lifted position until theyarrive at a point over the nextgrinding table B at a point which corresponds to station a of the firstgrinding table A. These lifting cams'are located at all points in thesystem where it becomes necessary to lift the plates of glass to avoidinterference or injury in moving the sheets from one table to the next.When it is desired to hold one of the spindles continuously in its upperposition, as in case of the breaking of the sheet carried thereby, thisis accomplished by manually moving the lever 56 farther to the rightthan the movement given by the cams. at which time the dog 59 engagesthe notch 59. lhis holds the spindle in raised position till the dog isreleased.

In orderito connectv the spindles together, the bars til are employed,such bars bein secured to the spindle casings/27 by means 0? the.vertical pins 3t which carry the rollers 3:2. The spindle casings takenin conjunction with the bars (ll constitute an endless chain. thespindle casings acting as the pintles in the chain. .ts indicated inconn ction with l' i es. l and the endless chain thus l tltlllttl passesaround the arocltets O, lit.) and ll which sprockets. asit e from thematter ot' their location. are substantially the same throughout and areshown in' detail in Fig. 11. 'lhese sprockets each consist of twospiders (3 and (it spaced apart and keyed to vertical shafts (t5. 'lheends of the spider arms are recessed so as to engage and fit around theportions 66 and 67 ot' the spindle casings 27. as indicated in Fig. 1.1.The eight sprockets l, shown in Fig.1. are all driven from the lineshaft 58 driven from the electric motor 5 by means of the belt 69 (Fig.4) passing around the pulley 70 (Figs. 1 and 2) on the line shaft.Upposite each pair of sprockets the shaft is pro ided with a wormdriving a worm wheel T53 upon a transverse shaft [3 (Fig. This shaft isprovided with the bevel pinions 74. engaging thehevel gears 73 on shortvertical shafts 76 (Fig. 3). These shafts 76 are provided attheir lowerends" with spur pinions 77 engaging spur gears TH 3) which are keyed tothe upper ends of the shafts 65 on which the sprockets (Fig. 11) arecarried. The other sprockets O, Q and R are all idlers.

Figs. 7 and 8 illustrate the means for applying glass to the suctionframes carried by the various spindles 25 preliminary to the grindingoperation on table A. In starting the operation, the sheets are placed'"pon the left-hand end 1e conveyor K, as shown. in Fig. 1. Th. conveyorcoinprises an endless belt passing around thesprockets 80 and 81 andsupported against downward :inoveinent of its upper flight by the angleiron tracks 82 (Fig. 7) which project beneath the chains comprising theendlcsscarrier and engage the rollers 83 located at the ends of thechain joints. Intermediate the chain joints and extending from thechain. on one side to the chain on the other are flat sheet metal plateswhich together form the continuous flat table K for supporting thesheets during the application of the' suction frames. As indicated inFig. 7, th'e track which carries the spindles and suctiogu framesextends -longitudinally over the endless carrier so that, as the platesof glass which are applied to the table M move along such table, thespindles with their suction frames are carried along at the same rate ofspe 1 upon the overhead track. Atthis time and before the application ofpressure means to the vacuum frames to cause the engagement of thesuckerswith the glass, the spindles are maintained in. elevated position by reason of the cam 85 which acts in the same manner as the camheretofore described in connection with Figs. 11 and 12. The cam 85 isinclined upwardly as indicated at 86 (Fig. 8) to release the spindleholding levers, so that at this point the vacuum devices are to engagethe glass plates on the table. The vacuum "frames are then carried alongbeneath the endless belts L located on each side of the center line ofthe track as indicated in l i-g. 7 in position to engage the upper endsof the members 44, which as indicated in'Fi'g. 10, are normally held intheir uppermost positionsby the springs The pressing down of thesemembers lowers the plates 4.1 and forces the ail-"out of the chambers50. At the same time, the plate -12 is pressed down tightly intocnqagemcnt with the top surface of the glass. lhis engagement ismaintained by the endless belts L until the vacuum frames pass frombeneath such belts. The movement from between these belts releases themembers l t of the sucker devices and under the influence of therelatively strong coil springs, the members eta are raised,'thus liltingthe plates 4 1. and enlarging the capacity of the chambers 50, thusproducing a suction cllcct which maintains the sheets of glass tightlyagainst the suckers, as described in mylatent No. 1,294,103.

Alter the plates have been ground and polished and have passed the lastpolishing table H, they are released upon anendless carrier M and bymeans of a pair of endless belts dcsignated bv. the reference letter Nin Fig. 1 which belts as well the carrier M correspond, except in theparticular here inafter set forth, to the similar devices for applyingthe plates as above described. The difference abovereferred to will beseen by reference to Figs. 8 and 7 which show in side elevation andsection, respectively, the release mechanism N. By reference to thesefigures, it Will be noted that along the upper edge of the angle irons88, which constitute the supporting track for the rollers, on theendless carrier, are placed a series'of rollers 89 which rollers arepositioned so that they lie beneath and engage the outer edges of thesuction frames 26. Above the endless carrier M is located the releasedevice N, in the form of a pair of endless belts N, corresponding .inlocation and function to the endless belts L, above described forapplying the suction devices- As the vacuum frames pass beneath belts N,such belts engage the members 44 pressing such members down, so that thevolume of the chambers 50 is reduced (Fig. 10)., thus releasing thesuction effect upon the plates of glass, and upon a slightly furthermovement, the rubber tipped ends 46 of the members 44 engage the glasssheets and ush them away from the sucker devices. his release action is-made possible b the fact that the edges of the vacuum rameare at thistime securely supported against downward movement by means of .therollers 89. In this way, the plates ar' released from the vacuum framesand d opped upon the endless carrier M from v 1ch they are removed by anoperator sta ding to the left of the release device N .ig. 1). As-thespindles and vacuum frames ass the left-hand end. of. tho'release devicetheir raising lovers are engaged by the inclined end of the lift ing cam85 which corresponds in position to the end 86 of the lifting cam 85,shown in Fig. 8, this liftin cam 85 being in the form of a semi-circ ewhich follows the curve of the track carrying the spindles and has oneand arranged to engage and operate the levers to lift the-spindles,which positionis maintained by the cam 85 u'itil the incline 86 isreached. This incline pernlits the spindles to lower as heretoforedescribed;

i The endless carriers M and K are driven f from the vertical shafts 91and 92' (Figs. 1 and 7) which in turn are di-iven by the sprocket chain93 passing around the three sprockets 94, 95 and 96 located at the u perends or. the shatts c5, 91 and'92 (Fig. 8 respectively. The sets ofbevel gears Q'l'and 98 on the shaft 91 drive thc'endless belts M whichthe sprocket chain 9?, extends.

and outer belt N, while on the other side of the machine a similardriving arrangement from the shaft 92 is provided for the endless belt Kand the outer belt L. The inner belts N and L are driven from a pair ofother vertical shafts 99 and 100, Figs. 1 and T, which shafts areprovided at their upper ends with sprockets 101 and 102 around Asindicated in Fig. 7, the inner belts L and are driven from the shafts100 and 90. respectively, by means of the sets of bevelgears 103 and 101.

The sprocket Q. made up of the spiders (t3 and 64 mounted on the shaft65 serves as an adjustment member for taking up the slack in the endlesschain or carrier made up of the vacuum frame spindles andllltCll)()-.t"l links. This sprocket is mounted for longitudinaladjustment in that its lower end is supported in a movable thrustbearing .05 (Fig. 8) and the shaft 65 above this point is carried in aframework made up of the channels 100 which are adjustablelongitrulinally from the post 107. This post preferably constitutes aportion of the structu e in which the grinding apparatus i installed.The thrust bearing 105 lies over a pair of T slots 108 which receive thebolts 10!) adapted to hold the bearing in any adjusted position. The sujiporting framework for the .shaft 05. made up of the channels 106, is

made adjustable with respect to the post .107 by means of the pair ofscrews 1l0 'wh1ch extend through the. blocks 111 carried by the channelsand engage at their inner ends against the sides of the post 107. Thechannels 100 are also supported upon the posts 112, also forming a partof the building structure in which the apparatus is installed, suchposts being provided with the transverse angles 11? engaging the undersides of the channels 10(3 and affording an additional support for suchchannels. After the framework 100 is 'j'iositioned by means of thescrews 110. it is secured in adjusted position by suitable belts orclamps (not shown).

The endless track which carries the vacuum frame spindles must also hemade adjustable as to length to correspoml to the =adjustn'ient of theframe 100 carrying the sprocket Q. and this is accomplished in' anydesired way, as

by having the track cut and overlapping,

and provided with suitable slots and securing bolts, an expedient wellknown in mechanics and requiring no illustration. I

The preferred construction of the polish ing tables is shown in Figs.-21 and 23. These tables are of annular form being cut out at the center114, and made up of a frame portion 115, which is of any approved-form,upon which is mounted a series of perforated steel plates 116 carryingrubber plates 11?. Upon the top of the rubber plates are cemented aseries of felt sheets 118 which sheet or plate 11T-is vulcanized on theper-' forated plate .116 and the rubber fills the perforations 1:20 anda very secure attachment of the rubber plate to the steel plate isafforded. the perforations 120 being sutiiciently -I1t1l1lQ10US to giveproper holding strength between the two plates. The steel plates 116 arepreferably of the shape indicated in Fig. 21 with the adjacent side ab*tting so that a crmtinuous surface is provide-1i.

The operation of the appara LES is as follows: Th 1 are applied by anoperator successively to'the endless carrier K and by this carrier theyare fed beneath the securing belts L. the feed of the plates being soowned with the endless, carrier supporting the vacuum devices that asheet is positioned beneath each o fsuch devices the plates and vacuumdevices pass between the two sets of endless belts. The pressure oftheendless lifting levers come into contact. with one of 1 the liftingcams, such as the cam 60 of Fig. 12. The spindles are thus raised sothat when the plates pass over the edge of. the grinding table, they areelevated above such table and not in danger of injury by contacttherewith. The further movement of the spindles on the endless carrierbrings them to the station a 5), at which point the holding cam for thespindle levers is bentupwards so that the spindles are. allowed todescend causing the glass to engage the surface of the-grinding table.Here sand is supplied to the table through the pipe 9, such sand beingthe coarsest from the grader U. The plates are from this pointconductedaround the table in the path indicated in Fig. 5. a progressive outwardmovement being given as the plates move circumferentially. so that whenthe s ation a is reached, the plate has passed completely across thegrinding portion of the table. During this movement successively finergrades have been placed upon the table from the pipes 10. 11 and 12, sothat. at the station (Z, a relatively tine grade of sand is employed andthe surface of the plate is ground to a considerable degree. At station.6, the spindles are again lifted by means of the overhead lifting cam,and they are maintained in this lifted ,;;'iosition'nn il-fl1eya'eachthe-"table B III o'l' tl abrasive which may he adhering to the plate.and for this purpose suitable wasnlug devices are provided for supplyinga stream of water to clean the plates as they pass. it may also bedesirable in this intermediate position. to tighten up the suckers uponthe glass and this may be accomplished, if desired. at this point. bythe use of other endless hells correspoiuling to the beltsK and li-JAfter the plates are applied to the grind in; table B. the procedure isthe same as heretofore described in connection with the table A except.that finer grades of abrasive are employed upon thistable. The procedureis also similar to that heretofore described, as the plates pass fromthe table 13 to the table C and over such table and from the table (l tothe table D and over that table. The mixture of sand and water from allthree tables A, ll and C is returned to the common sump V (Fig. 2) oilthe grader and each table is supplied with its proper series of gradesfrom such grader, ranging from the coarsest on table A to the finest iontahle C. Preferably the grinding with sand as an abrasive will'becompleted upon the table C and emery used for giving the final smoothupon the table D. The emery is preferably applied upon the same])1'lIlciple as used in connection with lhcapphcation 042' the sandthat. is the coarsest grade applied first, followed by suceessirclyliner 'raoes as the. plates progress around the cirerunl erence of thetable.

After the plates pass oil ol the lust table ll, they are thoroughlywashed oll' lud'ore passing upon the polishing); table l). "he path ofthe plates upon this table cor responds to the one heretofore describedin connection with the grinding table A. the plates bein; curriedircumlercntially of the tables and also-laterally so as to distributethe polishing" wear over the ent re surl'u c ol' the table. Thepolishing is preferably at z'fompiished b means of roupfc applied withwater in the usual way. 'lhe plates puss on the endless carriersiu-ccrsirelv from one table to the otbcr the poiishlnir beingconiplclcd upon the. last table ll. Alter pnssine' i'rom the table ll,the vacuum 'l'rnnies .iwilh their plates are carriedlwtween the endle sbelts N and ill. and, at. this point. the release of tl io' latcs isellccted. so that they drop down upon the-endless belt: M. and are.removed by an operator stetioncd at this point. The release. by theendless belt; M is accomplished in the-pressure ot" the belts N upon themembers 44- carried by the up per vacuum 1' latcs,' which pressure. rleas s the suction upon the. plates, after which the lower ends of themembers 44 engage the sheets of glass themselves anrhpush them away fromthe suckers. At this time the edges of the vacuum frame are supportedupon the rollers 89, so that such frames are securely held againstdownward movement, thus makim; the pressure of the belts N ef- 'fectiveto release the suckers.

Awvide variety of grinding tables niight be employed other than the oneillustrated in F gs. 5, 6, I19 and 20. One such form 'is illustrated inFigs. lito 18. 1n this form of construction, it is designed that the runner bars should be held removable in posi- -tion on the table bv meansof sulphur or some such composition which hnrdens at a temperature suchthat; it will serve to hold the bars in position until the temperatureof the composition is raised inorder to release the bars. this beingfrequently required in glass grinding tables in order to replace thebars worn away by the grinding operatiom .lle'l'erring to Figs. 15 and16, it will be noted that the fran'wwork 121 of the table has boltcd toits upper side a plurality of chambers 122 adapted to be supplied withsteam through the pipes 123 loi' the purpose of melting" the sulphurbath lil-t in which the rrmnc: ;bars 12:) are set. These runners may bemade in a variety of ways. As jllllS- tratlcd, they consist of a baseportion 126 provided with the upstanding diamond shaped blocks 127. Thespaces between the diamonds are tilled with plaster-oflaris to reducethe space for the lodgment of abrasive which would enter the spacesalmost; imnuuliately and be lost from service, thus redu ing thegrinding speed until. the spaces were lilled.- In order to seat. therunner bars at the proper level in the molten bath, the bearing pins 123are employed,-such hearing pins being ol the lorn'i indicated in Fig.1(3 and having their lower reduced ends fixed in recw-iscs 129 in thetop walls ol the chainhers 122. :uulharim: their upper cudstittin; intorc csses in the bottoms of the runner bars. such ends being: carefullymachined to a common level so that the level of the runncrba'rsis-delinitelv and accurately lixed. A l lthrlktllll applied to thechambers 1522 and the sulphurmelted. the runner barsare positioned andthe sulplu'r allowed to hard on. ll'hen it becomes nwcssary to replacethe'runuer bars, the sulphur is melted and the substitution readilymade.

Still another form of griri'nrlinp table illustrated in Figs. 2t t "37in which jlg'riud ing stonesol emery, carborunduin con1positimn or someother composition suitable for the purpose are employed in place. oi?the metal grinding bars heretofore described. With a const-riurtimi ofthis kind. the grindlug u be accomplished without the use of .il'll'rlire such as sand and emery, which is required in connection with metalgrinding surfaces, as heretofore described. With a grinding surface,such as that illustrated in Figs. Ztto 27, water is ordinarily usedinorder to facilitate the grinding operation and in some cases, this maybe appliedunder nressure against the surface ot the stones able to doboth the rough grinding and the smoothing with the stone or compositiongrinding surface.

As indicated in the drawings, 130 is the frame or bed 01 the table.which may be constructed in any desired form. upon which the stones aresecured by means of the bolts 131. These stones are preferably made ofthe size and shape indicated at 132 in. Figs. 26 and 27. port each otherat their side edges and are held securely in position by means of thebolts whose heads lie in the countersunk openings Fig. 14 illustrates amodified form of vacuum frame spindle construction in which the spring53, corresponding in function to the spring of Fig. 12, is mountedinside the spindle casing 27. The spring in this instance bearsagfainstthe thrust bearing 5:2, the loweumember of which engages a shoulder uponthe spindle-25 and normally holds such spindle yieldingly in itslowestposition. The track which carries this device and the arrangementof rollers for engaging the track identical with that of theconstruction of Fig. ii to 13, being similarly numbered with referencenui'nerals and requiring no further description. The spindle is raisedby means of the lever 13- 1 pivoted at 125 upon the bracket 136. Theinner forked end of this even-is provided with a pair of roll: [37adapted to engage the lower plate i the hall thrust bearing 138. theupper plate vi such bearingbeing held in position by Willie of the collal3!) pinned to the upper end of the spindle 25. The

outer end of the lever lJ-l icarries the rollerl-lU adapted to one .thecam (30 and is a so handle 141. When the roller l-lO circa the card(it), the inner end of the lever is raised lifting the spindle againstthe. tension of the sprin; 53 and when the roller moves oil of the camat its other end, the spring: moves the spindle and.

prorided with the vacuum frame and glass plate carried thereby downward.The lever 134 is provided with a downwardly projecting arm 14-2 and whenthe lever is thrown downward to a position below that to which it is Thestones fit against. and sup-- normally moved by the cam 60, the end ofthis arm 142 is engaged by the gravity operthe breaking of the glass,carried by the spindle. This dog 143 is released by moving its outer endupward. thus permitting the lever 13% to resume its normal position assecured by the action of the spring The grinding tables, which aremounted on tracks for transfer purposes as hereto" tore explained, arepreliminarily ground by placing thcmbeneath the runners of the ordinaryplate glass machine and rotatiiu, them. applying abrasive and wateruntil the grinding surface faced oil and trued up. These tables arepreferably made similar and. interchangeable so that they may be shiftedprogressively at intervals from the position A to the position 1). allowtable being placed at A when a shift is made. In this way the grindingfaces are partiall worn down and sn'ioot-hed before lrcltif! used. withthe liner abrasives and the !H.lf *'ll(.5t faces are employed where themore rapid grinding is desired and the rouglnmss will not injure thesurface of the glass.

It will be understood that the invention is not limited to theparticular embodiments of the plate carrying means. grinding tables andpolishing tables. illustrated and described. Other means than the vacuumholding means might be employed, such as embedding the plltes'inparaffin or other material readily melted to release the plates,although the vacuum device is the preferred means because of the case,of attaching and detaching the plates. The path of the plates over thetables might also be varied within a wide range, the only requirementbeing that the plates be carried over the tables in such way as todistribute the grinding wear, and the method of securing; this result tothe best advantage will be dependent upon the conditions to be met. Thepolishing tablls are described as covered with felt. on: it will beunderstood that other polishing; surfaces might. be employed, such forin stance as pitch, which is cheaper than felt and which lends itself tothe present apparatus since the polishing surface faces upard instead ol.lownward as is the case in the ordinary machine. llnder this conditionthe pitch holds the polishing material much better than it would it thepitch faced downwardly. The pitch is also easily applied and given aplane. surface by heating it and'allowing it to find itsown level on thetable. A. wood polishing table might also be used with pumiceor othersmoothing or-polishing powder, and means might lUU lfll)

